Bronsted acidic ionic liquid containing nucleophile I-methylimidazole and triphenylphosphine with 1,4-butane sultone and inorganic anions p-toluenesulfonic acid (PTSA) and trifluoroacetic acid (TFA) catalyzed Mannich reaction smoothly to afford beta-amino carbonyl compounds in excellent yield and less time. Effect of addition of two drops of water on the product yield and effect of anions and cations of the ionic liquid on the reaction rate have been investigated. The ionic liquid was easily separated from the reaction mixture by water extraction and was recycled four times without any loss in activity. (c) 2005 Elsevier B.V. All rights reserved.